When choosing headers for FI, the headers should have the shortest tube length possible, and Tri-Y is not needed.

The Dinan headers were designed to be the "icing" on the supercharger "cake". A major advantage of minimum length primary tubes is less heat soak underhood (running FI increases underhood temps, the added surface area of equal length primaries adds even MORE heat underhood).

Equal length Tri-Ys are best suited to non-FI engines.

Those who have tried to "chase" a few extra HP by optimizing exhaust pulse/merge/flow with FI, have found little gain after significant effort/cost. A simple pulley change will give you all the HP you could ever want, enough to grenade the motor.

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'03 X5 4.4 Sport, last of the M62s (8-03 build date)I believe in deadication to craftmanship in a world of mediocrity!

Those who have tried to "chase" a few extra HP by optimizing exhaust pulse/merge/flow with FI, have found little gain after significant effort/cost. A simple pulley change will give you all the HP you could ever want, enough to grenade the motor.

TiAgX5--- I honestly don't know. I will say that I trust Jed and from what I've read, have heard nothing to indicate that anyone has convinced him to change a thing. If you're correct, I'm guessing the difference on a real-world daily driver would be hard for me to notice at the wheel and at that level of perfection, I should have replaced the crank and pistons with lightweight versions and done a full extrusion hone on the heads to maximize flows, I did not. I'm just looking for the best I can get without building the space shuttle.

J. Belknap--- Thanks. How's your X doing? Love reading the story of how you landed that rig and got it home.

Crystalworks--- who knows. Dyno, dyno, dyno. I'll know then. I have found a slight difference in a domestic hp number compared to a German hp number in comparable displacement engines. If you've seen the inside of a 4.6is exhaust manifold, you'll know that just about anything should be better.
If anyone thinks that bmw didn't half-ass the exhaust manifold on the 4.6is, check this garbage out. Anything would be better.

We'll see soon enough. Love your rig by the way. Yours an BCredliner's are benchmarks. A few others too but from my first days reading in here, you two stuck out. My wife still won't let me mess with her exhaust. It's kill'n me.

When choosing headers for FI, the headers should have the shortest tube length possible, and Tri-Y is not needed.

The Dinan headers were designed to be the "icing" on the supercharger "cake". A major advantage of minimum length primary tubes is less heat soak underhood (running FI increases underhood temps, the added surface area of equal length primaries adds even MORE heat underhood).

Equal length Tri-Ys are best suited to non-FI engines.

Those who have tried to "chase" a few extra HP by optimizing exhaust pulse/merge/flow with FI, have found little gain after significant effort/cost. A simple pulley change will give you all the HP you could ever want, enough to grenade the motor.

For turbo, absolutely. Getting the turbine as close to the heads as possible is best to keep the gasses hot and moving. Heat is power. But for a blower...I think all you are trying to do is keep the air charge temp down so you don't lean out and detonate. But the real answer for that is probably a good intercooler, more fuel and a cheap heat extractor, not coating the pipe.

It looks nice and is probably a high-margin component for Dinan, though.